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| − | ! Mnemonic !! OPCode !! Bytes !! Cycles !! Meaning !! Skip Condition | + | ! Mnemonic !! OPCode !! Bytes !! Cycles !! Function !! Meaning !! Skip Condition |
|- | |- | ||
| − | | CLA || || 1 || 1 || A<sub>CC</sub> ← 0 || | + | | CLA || 90 || 1 || 1 || A<sub>CC</sub> ← 0 || Clear accumulator || |
|- | |- | ||
| − | | CMA || || 1 || | + | | CMA || 10 || 1 || 1 || A<sub>CC</sub> ← ~A<sub>CC</sub> || 1-s complement accumulator || |
|- | |- | ||
| − | | CIA || || 1 || | + | | CIA || 11 || 1 || 1 || A<sub>CC</sub> ← ~A<sub>CC</sub> + 1 || 2-s complement accumulator || |
|- | |- | ||
| − | | INC || || 1 || | + | | INC || 0D || 1 || 1 + skip || A<sub>CC</sub> ← A<sub>CC</sub> + 1 || Increment accumulator, skip if overflow || on overflow |
|- | |- | ||
| − | | DEC || || 1 || | + | | DEC || 0F || 1 || 1 + skip || A<sub>CC</sub> ← A<sub>CC</sub> - 1 || Decrement accumulator, skip if underflow || on underflow |
|- | |- | ||
| − | | CLC || || 1 || | + | | CLC || 0B || 1 || 1 || C ← 0 || Clear carry flag || |
|- | |- | ||
| − | | STC || || 1 || | + | | STC || 1B || 1 || 1 || C ← 1 || Set carry flag || |
|- style="background: #ccffcc;" | |- style="background: #ccffcc;" | ||
| − | | XC || || 1 || | + | | XC || 1A || 1 || 1 || C ↔ C' || Exchange carry flag with carry save || |
|- style="background: #ccffcc;" | |- style="background: #ccffcc;" | ||
| − | | RAR || || 1 || | + | | RAR || 30 || 1 || 1 || C → A<sub>CC</sub> → C || Rotate accumulator right through carry flag || |
|- style="background: #ccffcc;" | |- style="background: #ccffcc;" | ||
| − | | INM || || 1 || | + | | INM || 1D || 1 || 1 + skip || (DP) = (DP) + 1 || Increment RAM location pointed by DP, skip if result is zero || on (DP) = 0 |
|- style="background: #ccffcc;" | |- style="background: #ccffcc;" | ||
| − | | DEM || || 1 || | + | | DEM || 1F || 1 || 1 + skip || (DP) = (DP) - 1 || Decrement RAM location pointed by DP, skip if result is 0Fh || on (DP) = 0Fh |
|- | |- | ||
| AD || || 1 || | | AD || || 1 || | ||
Revision as of 07:09, 21 July 2018
The μCOM-4 ISA was an instruction set architecture composed of 80 instructions that were implemented by the NEC in their μCOM-4 family of microcontrollers. The μCOM-43 family implemented the complete ISA, while the μCOM-44 and μCOM-45 families implemented a strict subset of it. (Note that the μCOM-42 family had its own instruction set.)
Block diagram
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This section is empty; you can help add the missing info by editing this page. |
Registers
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This section is empty; you can help add the missing info by editing this page. |
Features
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This section is empty; you can help add the missing info by editing this page. |
Instructions
The μCOM-43 has support for all 80 instructions. The μCOM-44/μCOM-45 support a strict subset of it composed of 58 instruction. The majority of those 22 instructions deal with the added features only found in the μCOM-43 models.
| Mnemonic | OPCode | Bytes | Cycles | Function | Meaning | Skip Condition |
|---|---|---|---|---|---|---|
| CLA | 90 | 1 | 1 | ACC ← 0 | Clear accumulator | |
| CMA | 10 | 1 | 1 | ACC ← ~ACC | 1-s complement accumulator | |
| CIA | 11 | 1 | 1 | ACC ← ~ACC + 1 | 2-s complement accumulator | |
| INC | 0D | 1 | 1 + skip | ACC ← ACC + 1 | Increment accumulator, skip if overflow | on overflow |
| DEC | 0F | 1 | 1 + skip | ACC ← ACC - 1 | Decrement accumulator, skip if underflow | on underflow |
| CLC | 0B | 1 | 1 | C ← 0 | Clear carry flag | |
| STC | 1B | 1 | 1 | C ← 1 | Set carry flag | |
| XC | 1A | 1 | 1 | C ↔ C' | Exchange carry flag with carry save | |
| RAR | 30 | 1 | 1 | C → ACC → C | Rotate accumulator right through carry flag | |
| INM | 1D | 1 | 1 + skip | (DP) = (DP) + 1 | Increment RAM location pointed by DP, skip if result is zero | on (DP) = 0 |
| DEM | 1F | 1 | 1 + skip | (DP) = (DP) - 1 | Decrement RAM location pointed by DP, skip if result is 0Fh | on (DP) = 0Fh |
| AD | 1 | |||||
| ADS | 1 | |||||
| ADC | 1 | |||||
| DAA | 1 | |||||
| DAS | 1 | |||||
| EXL | 1 | |||||
| LI | 1 | |||||
| S | 1 | |||||
| L | 1 | |||||
| LM | 1 | |||||
| X | 1 | |||||
| XM | 1 | |||||
| XD | 1 | |||||
| XMD | 1 | |||||
| XI | 1 | |||||
| XMI | 1 | |||||
| LDI | 2 | |||||
| LDZ | 1 | |||||
| DED | 1 | |||||
| IND | 1 | |||||
| TAL | 1 | |||||
| TLA | 1 | |||||
| XHX | 1 | |||||
| XLY | 1 | |||||
| THX | 1 | |||||
| TLY | 1 | |||||
| XAZ | 1 | |||||
| XAW | 1 | |||||
| TAZ | 1 | |||||
| TAW | 1 | |||||
| XHR | 1 | |||||
| XLS | 1 | |||||
| SMB | 1 | |||||
| RMB | 1 | |||||
| TMB | 1 | |||||
| TAB | 1 | |||||
| CMB | 1 | |||||
| SFB | 1 | |||||
| RFB | 1 | |||||
| FBT | 1 | |||||
| FBF | 1 | |||||
| CM | 1 | |||||
| CI | 2 | |||||
| CLI | 2 | |||||
| TC | 1 | |||||
| TIT | 1 | |||||
| JCP | 1 | |||||
| JMP | 2 | |||||
| JPA | 1 | |||||
| EI | 1 | |||||
| DI | 1 | |||||
| CZP | 1 | |||||
| CAL | 2 | |||||
| RT | 1 | |||||
| RTS | 1 | |||||
| STM | 2 | |||||
| TTM | 1 | |||||
| SEB | 1 | |||||
| REB | 1 | |||||
| SPB | 1 | |||||
| RPB | 1 | |||||
| TPA | 1 | |||||
| TPB | 1 | |||||
| OE | 1 | |||||
| OP | 1 | |||||
| OCD | 2 | 2 | PORT[C,D] ← I7-I0 | |||
| IA | 2 | 2 | ACC ← PORT[A] | |||
| IP | 1 | 1 | ACC ← PORT[DPL] | |||
| NOP | 1 | 1 | no operation |
- μCOM-43 only
